Laser Kids

. : Circulation pump for dye laser (or cooling) : .

Sometimes it is needed to pump a liquid throughout some exotic system, like carbon dioxide laser cooling jacket or either a dye laser cell. In these cases the most important features of the pump is its small size, and ability to keep the solution clean. One of the most simple ways to make a clean and compact liquid pump is to use an adopted aquarium pump. Those are usually very clean (or else the fishes will die in their tank) and some of them can be small enough.

Here we'll learn how to adopt the fisssh tank pump for Your technical needs.

First of all You need go shopping in a search for a pump of suitable size. E.g. something like this:


Here's how it looks like from the inside:

Fish tank pumps usuallly have many stray cavities, where the liquid can stall and the wastes can be accumulated. A good idea is to open those cavities. Use a hand engraving tool (like dremel) and a diamond disc to cut the plastic carefully. It is important not to damage the motor, the turbine and the turbine chamber.

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In some pumps there can be some cooling chambers. Dont block them if You dont want the pump to become overheated.

The next step is to make a exhaust hose. This pump is intended for use in a narrow vessel, so its inlet will be directed to the bottom and the output hose will be directed to the top. The native exhaust pipe of the pump looks aside, so we should redirect it. As a hose we'll use a piece of metal pipe of a suitable diameter. (BTW a good source of metal pipes of different diameters is a telescopic antenna from a radio set).


Drill a hole for the new pipe and place it so that the pipe will go along the side of the pump body. Cut out the old (plastic) pipe. Its place and direction leaves a little use of it.

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The next stage is to glue the pipe to the pump body. Use a hand propane torch to heat the parts and to cover them with a thin uniform layer of hot-glue. It will help to make secure and precise attachement.

About the hot-glue rods: use black or transparent ones. the rods of white type appeared to be attacked by alcohol solutions.

Take a piece of thick plastic and make a lid for the side pipe.
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Cut the plastic pipe to a level, where the lid sitd and cover with a thick layer of hot-glue. You can use a propane torch here too.
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Thats all. The pump is ready.

Using a pvc pipe connect the output hose of the pump to the laser (or whatever else device You want to use). Put the pump into a vessel with the liquid. Use another pvc pipe to retun the backstream back to the vessel. Remember that the pump won't suck if its turbine chamber is not filled with the liquid. So it may be wise to take some efforts to let the liquid enter the pump in order to start circulation. Once the system is filled it will work all by itself without any further help.

Here is an example of the usage of the same pump in a capillary dye laser.